The present invention relates to an RF (radio frequency) fingerprint-based user authentication method, an approaching user detection method, a location registration method, and an apparatus for the same wherein there may be excellent effects in preventing a lost child, a missing elderly, a companion dog, etc. by utilizing the RF fingerprint, greater effects may be achieved in terms of security and safety compared to conventional fingerprint-based user authentication methods, and more accurate location registration of the wireless communications device for each store may be realized.